permit to add mobile or prefab shed

so i found a place that is within my budget and close to what i am looking for, except that it is a bit too tiny. I am not thinking of building more space rather adding a cute prefab shed or something. Do i need permits to do so in Los Angeles? The property offers a huge backyard and it would be great to have storage space that looks a bit nicer than the regular storage space.

Re: permit to add mobile or prefab shed

A building permit shall not be required for:4. One-story detached accessory building use as tool and storage sheds, playhouses and similar uses, provided the floor area does not exceed 120 square feet.